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Acute Cholecystitis

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Overview

Acute cholecystitis describes the inflammation of the gallbladder. In up to 90% of cases, it is secondary to gallstones (calculous cholecystitis) which obstruct the gallbladder neck or cystic duct, resulting in increased pressure in the gallbladder and inflammation. Over time, continued inflammation can lead to ischaemia and secondary infection, which can result in necrosis and gallbladder perforation and peritonitis.

In the remaining 10%, acute cholecystitis occurs due to causes other than gallstones (acalculous cholecystitis). It is thought to be due to bile stasis and thickening and is generally seen in critically ill people, fever and dehydration (leading to bile thickening), and prolonged total parenteral nutrition use.

Epidemiology

  • Acute cholecystitis is 3 times more common in women than men up to 50 years old
  • Gallstones may be present in up to 15% of the general population
    • Of these people, around 1-3% become symptomatic, mostly with biliary colic
  • Calculous cholecystitis makes up to 90% of cases

Risk Factors

Overview

Risk factors for gallstones and calculous cholecystitis are often remembered using the aide-mémoire ‘fair (white ethnicity), fat, fertile, female, and forty’. Other risk factors for gallstones are discussed in Gallstones.

Risk factors for acalculous cholecystitis include factors that lead to bile stasis (due to reduced/dysfunctional gallbladder movement) or bile thickening (due to dehydration) such as:

  • Sepsis, burns, trauma, major surgery
  • Prolonged fasting, starvation, or prolonged total parenteral nutrition use
  • Diabetes mellitus, end-stage chronic kidney disease, chronic heart failure, coronary artery disease, peripheral vascular disease
  • Some drugs – ceftriaxone and ciclosporin can form biliary sludge
  • Infection – Epstein-Barr virus infection, microsporidia infections in people with HIV 

Presentation

Overview

Since acute cholecystitis is most often caused by gallstones. Many patients have features of biliary colic which can become constant and severe, suggesting acute cholecystitis. Acute cholecystitis can present with:

  • Right upper quadrant pain:
    • Severe, constant, and lasts for hours
    • May radiate to the back, right shoulder, or interscapular region
    • There may be features of peritonism localised in the right upper quadrant
  • Systemic upset:
    • Fever suggests infection
    • Nausea and vomiting may be present
  • Murphy’s sign may be present:
    • Palpating the right upper quadrant and asking the patient to breathe in leads to inspiratory arrest due to pain as the gallbladder comes down and into contact with the examiner’s hand.
  • There may be features of peritonitis and sepsis

Referral and Investigations

Referral

If acute cholecystitis is suspected, admit the person to the hospital for further investigations, monitoring, treatment, and surgery.

Investigations

Investigations include:

  • Full blood count (FBC):
    • Leukocytosis may be present, suggesting inflammation or infection
  • Liver function tests (LFTs):
    • Usually normal
    • If LFTs are deranged, this may suggest Mirizzi’s syndrome, where the gallstone is impacted in the cystic duct, resulting in compression of the common hepatic duct, resulting in obstruction and jaundice.
  • Ultrasound:
    • The investigation of choice.
    • May show signs such as gallstones, a distended gallbladder, or thickened gallbladder walls

Differential Diagnoses

Biliary colic

  • Episodes of intermittent, crampy right upper quadrant pain
  • Symptoms often occur after eating meals, particularly fatty meals
  • Nausea is often common

Acute cholangitis

  • Features are similar to acute cholecystitis
  • Classically presents with Charcot’s triad: fever and chills, right upper quadrant pain, and jaundice

Viral hepatitis

  • Right upper quadrant pain may be associated with flu-like symptoms such as malaise, myalgia, lethargy, and nausea
  • There may be a history of risk factors such as foreign travel, intravenous drug use, getting tattoos etc.

Acute pancreatitis

  • Usually due to gallstones or consuming a large amount of alcohol over a short period
  • Often severe epigastric or periumbilical pain that radiates to the back
  • Cullen’s sign or Grey-Turner’s sign may be present in severe pancreatitis

Acute coronary syndrome

  • Pain is generally central chest pain or in the epigastrium and is described as squeezing or crushing
  • There may be radiation to the jaw or shoulder and associated sweating and pallor
  • Risk factors of cardiovascular disease may be present

Management

Overview

  • 1st-line: IV antibiotics and laparoscopic cholecystectomy within a week of diagnosis (ideally within 72 hours)
  • If unfit for surgery: IV antibiotics and refer for percutaneous cholecystostomy

Complications

  • Gangrenous cholecystitis:
    • Necrosis of the gallbladder occurs due to ischaemia and necrosis, which increases the risk of perforation
  • Gallbladder perforation – occurs in ~10% of people
    • Can lead to peritonitis and sepsis and has a mortality rate of up to 30%
    • People with perforation may have a short-term relief of symptoms as the gallbladder decompresses, but then peritonitis follows
  • Gallbladder empyema:
    • Continued inflammation and infection can lead to the formation of a collection of pus within the gallbladder (empyema)
    • Features are similar to acute cholecystitis but more severe, particularly higher fever and severe leukocytosis

Prognosis

  • Without treatment, acute cholecystitis may resolve spontaneously within 1-7 days but up to 30% of people require surgery or develop complications
  • In calculous cholecystitis, mortality rates are around 4%
    • Mortality rates increase up to 30% if perforation occurs
  • Acalculous cholecystitis has a worse prognosis, with mortality rates ranging from 10-50%

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